A magnetic card in which a magnetic stripe is arranged and an IC card on which an IC chip is mounted are known as cards from which information is read and into which information is written by a card reader. A card reader described in Patent Document 1 includes a magnetic head configured to read or write information from or into a magnetic stripe and an IC contact block configured to contact a contact terminal of an IC chip to perform communication with the IC chip. Further, the card reader includes a card transport path extending through a read/write position of the magnetic head and a contact position of the IC contact block, a card insertion port for inserting the card into the card transport path, and a card transport mechanism configured to transport the card inserted into the card transport path along the card transport path. Further, the card reader of Patent Document 1 includes a pre-head configured to detect a presence or absence of the magnetic stripe, when the card is inserted from the card insertion port into the card transport path, and a magnetic sensor configured to detect a presence or absence of the contact terminal of the IC chip. If the magnetic stripe is detected by the pre-head, the card reader drives the card transport mechanism to transport the card, and drives the magnetic head to perform read or write from or into the magnetic stripe of the card passing through the read/write position. Further, if the contact terminal of the IC chip is detected by the magnetic sensor, the card reader drives the card transport mechanism to transport the card to a contact position, and drives the IC contact block to perform communication with the IC chip.
The magnetic sensor configured to detect the contact terminal of the IC chip includes a core body, a first excitation coil, a second excitation coil, a detection coil, and a housing made of resin, the housing covering the core body, the first exciting coil, the second excitation coil, and the detection coil. The core body includes a core center unit around which the detection coil is wound, a first core end unit around which the first excitation coil is wound, the first core end unit protruding toward a side of a card transport path from the core center unit, a second core end unit around which the second excitation coil is wound, the second core end unit protruding toward a direction opposite to the card transport path from the core center unit, a first end surface at an opposite side of the core center unit at the first core end unit, and a second end surface at an opposite side of the core center unit at the second core end unit. A surface overlapping the first end surface in the housing is a sensor surface of the magnetic sensor, and opposes the card inserted into the card transport path from the card insertion port with a narrow gap. A surface overlapping the second end surface in the housing is an opposite surface facing an opposite direction of the sensor surface. When the first excitation coil and the second exciting coil are excited, a first magnetic field is generated in the direction from the sensor surface to the core center unit and a second magnetic field is generated in the direction from the opposite surface to the core center unit.
When the contact terminal of the IC chip is not present at the detection position opposite of the sensor surface, the first magnetic field and the second magnetic field are equal, and thus, the detection coil outputs no output (the output is zero). On the other hand, when the contact terminal is present at the detection position, a change due to the contact terminal of the IC chip is generated in the first magnetic field of the first excitation coil of the side of the card, and thus, an output corresponding to the change of the first magnetic field can be obtained from the detection coil. Therefore, based on the output from the detection coil, the contact terminal of the IC chip can be detected.